Photocatalytic degradation performance of antibiotics by peanut shell biochar anchored NiCr-LDH nanocomposites fabricated by one-pot hydrothermal protocol

The development of carbon-based mesoporous semiconductor composites with superior photocatalytic performance is of great importance for water remediation of organic pollution caused by antibiotics or dyes. In this work, series of novel peanut shell biochar anchored NiCr-LDH(NiCr-LDH/PSB) photocatalysts were constructed via one-pot hydrothermal method for photodegradation of ofloxacin and tetracycline antibiotics. The comprehensive characterization indicated that NiCr-LDH uniformly dispersed on biochar matrix and formed a three-dimensional flower-like mesoporous structure. Appropriate doping of PSB can remarkably improve the photodegradation performance of NiCr-LDH for ofloxacin and tetracycline removal under UV-light irradiation. The photodegradation efficiency is better than that of pristine NiCr-LDH and biochar alone. More importantly, the optimal NiCr-LDH/PSB (18 %) composite exhibited the superior photodegradation and mineralization performance for ofloxacin and tetracycline. The photocatalytic degradation activities of NiCr-LDH/PSB for OFX and TC were about 3.5 and 2.3 times than that of NiCr-LDH, respectively. After four successive operations, the removal efficiency decreased by less than 20 %, suggesting that the as-synthesized NiCr-LDH/PSB has a good application prospect. Furthermore, a possible photocatalytic mechanism with •OH and •O2− as the main active species was proposed on the basis of photoelectrical properties, active species trapping and ESR tests. The study offers a novel idea for the fabrication of biochar anchored LDH system with excellent synergic adsorption and photocatalytic performance for the removal of antibiotic wastewater.